Man-of-Leisure Was CableCARD really that big of a factor? I’d be surprised if even 5% of customers were using them.
Even at the peak, the numbers were lower than that, and in the last available reporting period (before reporting was suspended) the numbers were less than 1%. All the majors have stated that the numbers have only gone down, and are now are noise in the TV service customer numbers (if 100% of the CableCARD customers ended service all at the same time it would probably not even be noise in the around 2 to 3% of monthly churn numbers, and even if noise, it would be a single month’s jitter noise).
As @MacLeech said, the issue was that the operators using Linear QAM were required to support CableCARD customers (the very small “mom and pop” operators could get a CableCARD waiver, but not the majors).
Times have changed, and at least a few of the operators, even those still using Linear QAM, have decided to end CableCARD support entirely, but, at least for now, most of the majors still tolerate their CableCARD users (but mostly will no longer provide one, only accelerating the decline in the total numbers).
At this point, none of the majors will be making technology decisions for their future deployments based on whether those technologies support CableCARDs now that all the mandates have been lifted (as before, existing users may be tolerated until they get in the way of something else, and existing plans will probably continue to be implemented). Cases in point: Verizon’s new NG-PON2 (and ONTs) requires moving to IPTV, Comcasts new D4.0 FDX deployments requires moving to IPTV, Charter may or may not also choose an IPTV deployment requirement in later phases (they have neither confirmed nor denied any such plans, but they are heavily pushing their IPTV only Xumo boxes, and have publicly stated IPTV is the expected future for their plant). But the past legacy of needing to support CableCARD users still impacts some current deployments.